Re: Concerns about AMD64 port
John Goerzen <jgoerzen@complete.org> writes:
> On Thu, Feb 05, 2004 at 06:38:07PM +0100, Goswin von Brederlow wrote:
> > > It's not wasted because it would get used a fair bit before the mixed
> > > system is available. True, once the mixed system is complete it
> > > wouldn't be needed anymore, but that doesn't make the time spent on it
> > > wasted just because it'll be depreceated some time in the future.
> > > That's a bit like saying that building a car now is work wasted because
> > > in 2 years a new model will be out.
> >
> > You can use the existing i386 or multiarch setup just fine right
> > now. You are proposing to design a unicycle on the way from the
> > bicylce to a tricycle.
>
> What multiarch setup? We have none.
>
> Or do you call a 64-bit chroot multiarch?
debian-amd64 on alioth. You don't have to use a chroot and most of the
debian-amd64 people don't anymore. Its a good idea to test upgrades
and design changes in a chroot first but that doesn't mean you can#t
use it for / too.
> > Its also a hell of a lot easier to bootstrap the 64 bit packages with
> > the existing 32 bit packages supplying build-depends. A lot of
> > Depends/Build-Depends cycles can be broken that way.
>
> I will make this pledge here: If we are willing to get a 64-bit port
> going now, I am personally willing to solve any such build-dep cycle
> that arises.
Are you aware that you just pledged yourself to port ~500 debs
including XFree and latex for a pure amd64 port?
> I can make that pledge knowing that this is neither a hard nor an
> intractable problem. Having just solved several of those on netbsd-i386
> last week.
Netbsd is probably a fair bit smaller in that regard and much easier
to do, since a lot of people already did it.
> > you don't want multiarch on amd64 you are welcome to start a 64bit
> > only repository. Once you get base+build-essential setup I can run a
> > buildd for it within a days notice. But you would realy duplicate a
> > lot of work that multiarch people are already working on.
>
> Can we get this repository on ftp.debian.org as a real port?
I doubt you can get it before sarge is out. The consensus of all the
debian-amd64 people so far was to wait for sarge to get out of the way
before sending in amd64 patches that would possibly (definitly?)
introduce new bugs and build failures.
> Anyway, doesn't the chroot on alioth already have this?
There is no chroot on alioth. Its not even an amd64. Alioth only has
a "minimal" apt repository with the biarch tools needed to compile a
64bit kernel and all debs needed to get a chroot and mini buildd setup
easily. And thats already 1G.
I stopped adding stuff to the repository when i had everything to
start the mini buildd. Now I'm waiting for glibc fixes.
> > > It's only a problem of putting it in the 'right' place if you want the
> > > 'right' place to be /lib64 or /usr/lib64 instead of just building a
> > > pure-64bit port.
> >
> > Thats whats needed for compatibility with existing guidelines and
> > distributions.
>
> And that is fairly trivial attainable for a pure-64bit port as well.
Any compatibility with existing distributions puts you in the same
position as the multiarch: You need a biarch glibc.
> > Which isn't realy crippled. Apart from speed, which is hardly a
> > pressing factor normaly, the only advantage of amd64 is the bigger
> > address space.
>
> Speak for yourself; the speed is a pressing factor for me. Otherwise,
> why would i have just not bought a Xeon?
So what application do you have that needs all the speed and why can't
you compile just that and its lib for 64 bit? And do you think you
will get more than a few % speed out of porting it?
Its probably cheaper to buy a slightly faster cpu than to port
something, unless you consider your time free.
> > For anyone willing to run unstable Debian has a multiarch port on
> > alioth *today*. Whats needed for it to mature (and to catch up to
> > sarge) is people willing and able to invest time into fixing
> > libc6. Thats the most pressing issue I'm aware of.
>
> Can you summarize, or post a link to an existing summary, of exactly
> what is wrong there?
>
> -- John
Talk to Mithrandir on #debian-amd64@irc.debian.org. He is working on
it so he knows best.
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